Hydromorphone and hydrocodone are semi-synthetic narcotics used as analgesics and antitussive drugs. Both compounds can be prepared by transition metal catalyzed isomerization of morphine and codeine, respectively.

Application of heterogeneous catalysts such as finely divided Pt and Pd or Pt, Pd and Ru anchored to solid supports for this transformation was disclosed in a number of patents (DE 365 683, DE 380 919, DE 607 931, DE 617 238, DE 623 821, U.S. Pat. No. 2,544,291, U.S. Pat. No. 2,577,947, U.S. Pat. No. 6,512,117, U.S. Pat. No. 6,589,960, WO 2005/100361). Unfortunately, the described heterogeneous catalysts often demonstrate low selectivity, which results in low yield of the desired product and/or tedious purification procedures.
Isomerization of allylic alcohols to the corresponding ketones catalyzed by soluble transition metal complexes is a well documented process (see, for example, McGrath, et al. Organometallics, 1994, 13, 224 and references cited therein). However, despite the fact that morphine and codeine are allylic alcohols, there are only few known examples of successful application of homogeneous catalysis for the isomerization of these compounds to hydromorphone and hydrocodone (WO 98/05667, US 2005/0124811 A1).
Thus, a need exists for new catalysts capable of converting morphine/codeine to hydromorphone/hydrocodone.